TT 

2U 
B5 


UC-NRLF 


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LIBRARY 

OF  THE 

UNIVERSITY  OF  CALIFORNIA. 


Class 


Autogenous 

of  Metals 


THE    BOILER    MAKER 

17  Battery  Pi 


1  Qftft 


Autogenous  Welding 
of  Metals 


A  description  ot  the  application  of  Auto- 
genous Welding  to  the  manufacture  of 
Tanks  ;  Gasometers,  Receptacles  for  Liq- 
uids or  Gases,  with  or  without  pressure  ; 
Steam  and  Hot  Water  Boilers,  Kettles  ; 
Small  Boats;  Automobiles;  Piping,  either 
steel,  copper  or  brass  ;  and  Coils  of  all 
kinds  ;  and  also  its  application  to  Repair- 
ing old  or  new  Castings  injured  through 
such  defects  as  blow-  holes,  cracks,  etc. 
Its  application  to  the  Manufacture  of 
Steel,  Brass,  Bars  and  Plates,  and  to  the 
Destruction  of  Metals,  Structures,  etc. 


Translated  from  Reports  of  the  National  School  of  Arts  and  Trades 
of  France 


By  L.  L.  BERBER,  M.E 

L*AAIIV* 


•  F  THE 

N1VERSITY 


NEW    YORK 

THE    BOILER    MAKER 

17   Battery   Place 
1908 


GENERAL 


Copyright,  1908 
THE    BOILER   MAKER 


Autogenous   Welding  of   Metals. 


CHAPTER  I. 

HIGH     TEMPERATURES     FOR     INDUSTRIAL     PURPOSES     OBTAINED     BY 
MEANS  OF  BURNERS. 

DEFINITIONS. 

The  so-called  oxyacetylene  welding  of  metals  consists  in  the 
assembling,  by  means  of  more  or  less  complete  melting  of 
metallic  pieces  of  the  same  nature,  the  surfaces  of  which  are 
brought  in  contact  at  a  high  temperature,  without  interposition 
of  a  different  metal  from  that  constituting  the  pieces. 

By  extension,  the  name  "oxyacetylene"  has  been  applied  to 
welding  made  between  pieces  of  different  metals  which  can, 
however,  form  a  resisting  alloy.  On  the  other  hand,  the  in- 
terposition of  another  neutral  metal  capable  of  forming  a 
more  or  less  perfect  assembling  between  the  two  similar  or 
different  metals  in  presence  constitutes  a  "brazing,"  and  tin 
soldering  is  among  that  class. 

The  melting  points  of  the  various  metals  being  very  dif- 
ferent, the  oxyacetylene  wdding  of  a  certain  number  of 
metals  (lead,  for  instance)  has  been  easily  accomplished  for  a 
number  of  years,  while  its  application  to  iron,  steel,  brass,  etc., 
has  been  more  difficult  and  required  entirely  different  pro- 
cesses. 

We  shall  consider  these  latter  processes  only,  and  if  we 
were  to  refer  to  the  definition  of  oxacetylene  welding  we 
would  have  to  establish  the  following  classification: 

Welding  with  a  blacksmith's  forge. 

i 

17928.3 


Hydrothermal  welding. 

Electrical  welding. 

Oxyhydric  blow-pipe. 

Oxyacetylenic  blow-pipe. 

Illuminating  gas  and  oxygen  blow-pipe. 

However,  the  processes  using  gas  burners  affording  numer- 
ous advantages  to  the  ordinary  work  of  the  various  industries, 
only  the  following  processes  are  actually  to  be  considered : 

Oxyhydric  burner   (oxygen  and  hydrogen). 

Oxyacetylenic  burner  (oxygen  and  acetylene). 

Oxygas  burner   (oxygen  and  illuminating  gas). 

COMPARISON  BETWEEN   THE  VARIOUS   TYPES   OF   BLOW-PIPES. 

The  oxygen  and  hydrogen  used  in  the  oxyhydric  burner  may 
be  obtained  from  the  tanks  in  general  use  in  the  trade,  in 
which  these  gases  are  compressed  under  a  pressure  of  300  to 
i, 800  pounds  per  square  inch.  They  may  also  be  generated  on 
the  spot  by  the  electrolysis  of  water,  and  then  compressed 
under  a  pressure  of  300  pounds,  to  be  then  distributed  to  the 
burners  through  appropriate  pipe  lines. 

In  general,  this  latter  principle  is  not  applied  because  of  the 
costly  apparatus,  the  experienced  personnel  and  the  expensive 
maintenance  which  it  requires.  Moreover,  the  decomposition 
of  the  water  into  its  elements  and  the  fact  that  the  hydrogen 
and  oxygen  pipe  lines  must  of  necessity  run  close  to  each 
other,  constitute  a  source  of  danger  and  render  impossible  the 
production  of  these  gases  in  the  consumer's  plant. 

As  a  rule  all  the  oxyhydric  burners  in  use  are  supplied  from 
ordinary  tanks  containing  the.  gases  under  pressure.  The 
actual  average  prices  are:  oxygen,  4  cents  per  cubic  foot; 
hydrogen,  about  I  cent  per  cubic  foot. 

For  Oxyacetylenic  burners  commercial  oxygen  is  used ;  the 
acetylene  comes  from  one  of  the  following  sources :  Dissolved 
acetylene  in  tanks,  where  the  gas  is  dissolved  in  acetone, 
impregnating  a  porous  material  and  under  an  average  pressure 
of  150  pounds ;  acetylene  generating  apparatus,  producing  the 
gas  on  the  spot  under  a  pressure  of  about  10  pounds  when- 

2 


ever  required.  The  actual  average  prices  are  as  follows: 
Oxygen,  4  cents  per  cubic  foot ;  dissolved  acetylene,  2  cents 
per  cubic  foot.  The  cost  price  of  acetylene  produced  on  the 
spot  by  generating  apparatus  is  about  I  cent  per  cubic  foot. 

Oxygas  blow-pipes  are  supplied  with  ordinary  commercial 
coal  gas  from  the  distributing  pipes  of  special  tanks.  In  the 
following  calculations  illuminating  gas  has  been  reckoned  at 
the  rate  of  $1.25  per  thousand  cubic  feet : 

Oxy acety- 
lene Oxyhydric        Oxygas 
Mixture.        Mixture.        Mixture. 

Temperature  obtained  by  com- 
plete combustion  of  the  mix- 
ture about 6,219°  4>I56°  3^32° 

Number  of  B.  T.  U.  obtained 
by  complete  combustion  of  i 
cubic  foot  of  combustible  gas.  i  ,5  70 .  290 .  61 6 . 

Quantity  of  pure  oxygen  theor- 
etically necessary  for  the  com- 
plete combustion  of  i  cubic 
footof  combustible  gas. cu.  ft.  2-5io  0.620  0.923 

Quantity  of  pure  oxygen  fed  to 
the  blow-pipe  per  cubic  foot 
of  combustible  gas  (results  of 
experiments) cu.  ft.  1-300  •  0.250  0.670 

Respective  quantities  of  the 
gases  to  be  fed  to  the  blow- 
pipe to  obtain  1,000  B.  T.  U. 

cu.  ft.  A\666        H3.846        Gi.Si 

O     .866          O  .96          O  i. 21 

Cost  price  of  1,000  B.  T.  U. 
(according  to  above  prices): 

Dissolved  Ac cts.  4 . 797 

Generator  Ac cts.  4.13  7.69  5.066 

The  above  figures  will  be  very  useful  in  making  comparisons 
hereafter. 


From  the  point  of  view  of  their  use  the  oxyacetylene  weld- 
ing processes  may  be  classified  as  follows : 

Processes  admitting  of  the  easy  transportation  of  the  welding 
apparatus  to  the  places  where  the  work  is  to  be  done ;  dissolved 
acetylene  welding;  oxyhydric  welding. 

Processes  necessitating  the  transportation  of  the  piece  to  be 
welded  to  a  fixed  welding  station;  oxyacetylene  welding,  the 
acetylene  being  supplied  by  a  generator ;  illuminating  gas 
welding. 

PORTABLE     OXYACETYLENE     WELDING     APPARATUS.        DISSOLVED 
ACETYLENE.       OXYHYDRIC. 

(a)     Comparative  Cost  Prices  of  the  Two  Systems. 

The  cost  price  of  1,000  B.  T.  U.  can  easily  be  established, 
knowing  the  price  of  the  gases  used  and  the  quantity  of  prac- 
tically pure  oxygen  fed  to  the  blow-pipe  for  the  combustion  of 
i  cubic  foot  of  combustible.  Figuring  on  4  cents  per  cubic 
foot  for  oxygen,  I  cent  per  cubic  foot  for  hydrogen,  and  2 
cents  for  dissolved  acetylene  per  cubic  foot,  it  will  be  found 
that  1,000  B.  T.  U.  (acetylenic,  dissolved  acetylene)  cost  4.797 
cents ;  1,000  oxyhydric  B.  T.  U.  cost  7.69  cents. 

But  the  cost  of  workmanship  must  also  be  taken  into  ac- 
count in  the  fixing  of  the  cost  price  of  the  welding.  In  con- 
sequence of  the  lower  temperature  of  the  oxyhydric  mixture 
the  time  required  to  melt  the  metal  is  naturally  longer  with 
this  process  than  with  the  acetylene,  and  the  result  is  that  for 
a  given  amount  of  work  the  cost  of  workmanship  is  higher. 
The  following  curves  (Fig.  i  and  2),  obtained  from  the 
results  of  numerous  trials,  clearly  show  this  difference. 

The  superiority  of  each  one  of  the  constituting  elements  of 
the  cost  price  of  the  acetylenic  mixture  over  that  of  the 
oxyhydric  mixture  is  also  apparent,  and,  greater  still,  in  the 
total  of  this  price.  Thus  experience  has  shown  .that  the  cost 
of  welding  sheet  metal  of  ^4  inch  thickness  by  the  dissolved 
acetylene  process  is  only  half  of  that  of  the  oxyhydric  mixture, 
(fr)  Comparison  of  the  Two  Processes  from  the  Points  of 
View  of  Easiness  of  Handling  and  Applications. 

4 


When  buying  an  apparatus,  however  good  and  economical 
its  principle  may  be,  it  is  very  important  to  consider  the  ques- 
tion of  how  easily  the  necessary  force  of  men  will  be  trained 
to  its  use,  and  to  be  able  to  indicate  the  well-defined  mode  of 
its  regulating.  In  the  oxyacetylene  process  of  welding,  more 


2  3          4  6  6  7  8  9 

Thickness  of  sheets  to  weld  In  millimeters. 
FIG.  1. 


10 


than  in  anything  else,  the  regulating  is  of  supreme  importance, 
as  the  quality  of  the  finished  work  is  essentially  dependent  on 
it,  because  an  excess  of  either  the  combustible  or  of  the  sup- 
porter of  combustion  may  cause  an  alteration  of  the  metal  and 
its  properties. 

In  the  course  of  a  recent  dispute  the  partisans  of  the  oxyhy- 
dric  mixture  announced  the  opinion  that  the  oxyacetylene 
blow-pipe  produced  brittle  welds.  The  inaccuracy  of  this 

n 


9.00 


8.00 


Curve  of  total  cost,  gas  and 
workmanship. 
Curve  of  cost  in  gas, 
(workmanship  not  included.) 


345         67         8         9        10 

Thickness  of  sheets  to  weld  in  millimeters. 


FIG.  2. 


assertion  was  demonstrated,  particularly  at  the  Society  of  the 
Civil  Engineers  of  France  (see  official  report  of  the  meeting 
of  March  16,  1906),  and  with  the  corroboration  of  extensive 
actual  trials  it  had  to  be  admitted  that  the  oxyacetylenic  as 
well  as  the  oxyhydric  mixture  gave  perfect  results,  the 
defects  noted  with  one  or  the  other  systems  being  due  to  a 
defective  regulation  of  the  flame. 

The  combustion  of  the  oxyhydric  mixture  produces  a  flame 
of  very  small  illuminating  power,  the  purple  and  red  color  of 
which  it  is  almost  impossible  to  describe.  In  the  proportions 
required  to  obtain  a  perfect  weld,  the  flame  of  the  oxyacety- 
lenic mixture  is  characterized  by  a  white  central  part  very 
neatly  outlined,  surrounded  by  an  almost  colorless  flame.  The 
least  variation  in  the  proportion  of  the  combustible  gas  and  the 
gas  supporting  the  combustion,  immediately  modifies  the  shape 
and  the  color  of  this  central  part,  noticeable  even  to  the  most 
inexperienced  eye.  This  remarkable  property  of  the  oxy- 
acetylenic flame  is  applied  to  the  regulating  of  the  blow-pipes, 
and  enables  anybody  to  discover  at  a  glance  the  proper  or 
defective  composition  of  the  mixture. 

Unfortunately,  this  sure  and  practical  method  of  regulating 
cannot  be  applied  to  the  oxyhydric  mixture,  which  has  no 
well  defined  characteristic  flame,  and  the  excess  of  one  or  the 
other  gases  causing  variations  of  color  that  the  eye  cannot 
detect.  Undoubtedly,  at  first,  the  oxyhydric  blow-pipe,  placed 
into  the  hands  of  a  few  very  smart  workmen,  enabled  them 
to  practically  obtain  excellent  results.  But  as  its  use  became 
more  general  it  was  very  soon  found  that  in  a  number  of 
cases  there  was  no  welding,  but  simply  that  two  damaged 
parts  of  metal  were  merely  stuck  together.  The  problem  to 
be  solved  was  the  automatic  supply  of  the  gases  in  the  required 
proportion :  the  high  pressure  under  which  the  tanks  were 
filled  when  put  into  service  had  to  be  taken  into  account,  as 
also  the  decrease  of  said  pressure  in  the  course  of  the  con- 
sumption of  gas;  and,  finally,  the  variable  flow  required. 

In  the  instruments  then  invented  a  regulating  valve  was  set 
in  motion  through  the  elasticity  of  reciprocating  parts  and 

7 


springs.  This  valve  was  raised  only  a  few  tenths  of  a  milli- 
meter, and  its  almost  capillary  orifice  was  subject  to  frequent 
partial  obstructions.  The  working  of  such  systems  is  most 
uncertain,  and  the  results  obtained  are  by  no  means  up  to  the 
expectations.  At  the  present  time  the  problem  has  not  as  yet 
been  solved,  and  this  difficulty  of  regulating  the  flame  is  cer- 
tainly one  of  the  reasons  which  retard  the  development  of 
oxyhydric  welding. 

The  temperature  of  6,000  degrees,  produced  by  the  oxyacety- 
lene  blow-pipe,  was  at  first  considered  as  an  inconvenience  by 
those  who  thought  that  the  metal  to  be  soldered  would  itself 
reach  that  temperature,  which  was  much  higher  than  its  melt- 
ing point,  and  that  its  properties  would  consequently  be  altered. 
But  this  criticism  is  absolutely  without  foundation,  because 
when  welding  the  metal  is  not  in  the  same  condition  as  if  it 
were  in  a  furnace  subjected  to  the  action  of  the  blow-pipe, 
and  the  melting  part,  being  in  contact  with  a  part  that  is  not 
yet  melted,  has  not  the  same  temperature  as  the  flame.  In  the 
case  of  a  metal  plate,  for  instance,  if  the  action  of  the  blow- 
pipe is  kept  up  longer  than  is  necessary,  the  melted  metal 
falls  in  drops,  making  a  hole  in  the  plate,  but  its  temperature 
is  not  raised  considerably  over  the  melting  point.  The  6,000 
degrees  for  which  the  acetylene  blow-pipe  was  blamed  was,  on 
the  other  hand,  used  by  the  acetylenists  as  an  argument  in  its 
favor.  The  quickness  in  reaching  the  melting  point  renders 
possible  the  welding  of  thick  plates  and  pieces  of  great  bulk, 
such  as  steel  castings.  This  cannot  be  done  with  the  oxy- 
hydric blow-pipe,  which  does  not  cause  the  melting  of  the 
metal  on  account  of  the  low  temperature  of  its  flame,  and  of 
the  greater  relative  losses  of  heat  by  conductibility  which  are 
the  result  thereof.  The  oxyacetylene  blow-pipe,  by  its  rapid 
action,  reduces  to  a  minimum  the  heating  of  the  parts  adjoin- 
ing the  weld,  and  with  it  close  brazings  and  many  other  repairs 
may  be  made  that  would  otherwise  be  rendered  impossible  by 
the  extensive  softening  of  the  metal  under  the  slower  action 
of  other  processes. 

Experience  shows  that  for  the  average  thickness  of  l/4  inch 


to  Y$  inch  the  welding  operation  that  can  be  performed  with 
a  50  cubic  foot  tank  of  liquid  acetylene  (weighing  55  pounds), 
and  a  70  cubic  foot  tank  of  oxygen  (weighing  50  pounds),  will 
require  at  least  495  cubic  feet  of  hydrogen  and  125  cubic  feet 
of  oxygen  by  the  oxyhydric  process,  or  four  tanks  of  hydrogen 
weighing  90  pounds  each  and  one  55-pound  tank  of  oxygen. 
In  other  words,  where  a  io5-pound  oxyacetylene  apparatus 
will  do  the  work  without  any  taking  apart  of  pieces,  a  415- 
pound  oxyhydric  installation  will  be  necessary,  and  will  re- 
quire the  hydrogen  injector  to  be  taken  off  and  put  back  three 
times  and  the  oxygen  injector  once. 

In  cases  where  the  metallurgical  plants  are  not  near  to  the 
establishments  producing  the  gases  required  it  will  be  neces- 
sary, in  the  selection  of  the  apparatus,  to  take  into  account 
the  important  difference  in  the  number  of  B.  T.  U.  obtained 
per  cubic  foot  of  material  which  exists  between  the  oxyacety- 
lene and  oxyhydric  processes,  and  which  considerably  affects 
the  cost  price  of  welding  through  the  cost  of  transportation 
of  the  tanks.  ^  Conclusions. 

On  the  whole,  the  dissolved  acetylene  process,  while  on  an 
equal  footing  with  the  oxyhydric  process  in  point  of  expense 
of  installation  and  maintenance,  is  very  superior  from  the 
following  points  of  view,  which  are  the  only  ones  to  be  con- 
sidered in  ordinary  work : 

Price  of  the  gases  used.  ^ 

Cost  of  workmanship.         ^  Production  being  equal. 

Cost  of  transportation.     J 

Easy  regulation  of  the  flame. 

Ability  to  weld  large  pieces. 

On  the  other  hand,  the  oxyhydric  process  is  to  be  preferred 
to  the  oxyacetylene  method  in  the  welding  of  very  thin  plates 
(less  than  1/32  inch),  which  requires  less  ability  on  the  part 
of  the  workman,  because  its  action  is  not  as  rapid,  the  fusing 
speed  of  the  mixture  not  as  high.  This  speed,  indeed,  with 
an  oxyacetylene  blow-pipe  operated  by  an  inexperienced  man, 
may  cause  holes  in  the  piece  that  is  being  welded,  which, 
however,  it  is  easy  to  repair. 


INSTALLATIONS    OF    STATIONARY    WELDING    APPARATUS. 

ist.  Oxyacetylene  supplied  by  a  generator. 
2d.  Oxygas — Illuminating  gas  supplied  by  the  ordinary  dis- 
tributing pipes. 

(a)      Comparative  Cost  Prices  of  Both  Systems. 

A  preceding  table  has  shown  that  the  cost  price  of  1,000 
B.  T.  U.  obtained  by  what  shall  hereafter  be  termed  "gen- 
erator acetylene,"  is  4.13  cents,  while  the  cost  price  of  1,000 
oxygas  B.  T.  U.  is  5.066  cents,  taking  as  a  basis  the  following 
prices:  Acetylene,  2  cents  per  cubic  foot;  illuminating  gas, 
$1,25  per  1,000  cubic  feet;  oxygen,  4  cents  per  cubic  foot. 

The  two  following  diagrams,  Nos.  3  and  4,  show  the  results 
of  many  experiments  and  the  economy  of  the  oxyacetylene 
mixture. 

(b)  Comparison  Bctiveen  the  Two  Processes  from  the  Points 
of  View  of  Easy  Handling  and  Applications. 

The  oxyacetylene  flame  is  undoubtedly  much  easier  to 
regulate  than  that  of  illuminating  gas ;  however,  with  practice 
the  oxygen  flame  can  be  regulated.  For  this  reason  we  shall 
.not  take  into  account  the  more  or  less  easy  regelating  of  the 
flame,  as  we  have  done  in  comparing  the  oxyhydric  and  oxy- 
acetylene mixtures. 

The  oxygas  welding  can,  of  course,  only  be  used  in  cities 
where  there  are  coal-gas  plants.  On  the  contrary,  the  oxy- 
acetylene welding  may  be  installed  anywhere. 

The  expense  of  installing  an  acetylene  welding  plant  is 
necessarily  greater  than  in  the  case  of  coal  gas,  owing  to  the 
price  of  the  generator,  which  is  not  to  be  considered  in  the 
case  of  a  coal-gas  plant. 

This  advantage  of  coal  gas  is  counterbalanced  by  the  incon- 
veniences resulting  from  the  low  temperature  and  the  great 
volume  of  the  flame :  impossibility  of  practically  welding 
thicknesses  of  1/6  to  1/5  inch,  considerable  losses  of  heat 
through  radiation,  which,  for  ^  inch  thickness,  are  a  great 
nindrance  to  the  workman. 

Besides,  it  must  be  remembered  that  coal  gas  for  illuminat- 

10 


Time  necessary  to  weld  per  meter, 
in  minutes. 

H^  t—»t-?t<3COCO'*-4-CJl 

cncci  l>'  S  e?  S  55  S 

.  xi 

•\e^T 

r// 

^3^ 

^ 

*x 

4^1 

^ 

^ 

^x^ 

—  ^ 

e^ 

^$ 

pi> 

^ 

r 

1234567            89           10 

Thickness  of  sheets  to  weld  in  millimeters. 
Pig.  3* 


st  per  meter  to  weld,  in  francs, 

P  0  M  N-  to  10  00 

S  8  8  g  8  S  8 

—~  —  Curve 
workn 

of  total  cost,  (gas  and 
lanship.) 
of  cost  of  gas,  (workmanship              / 
eluded.)                                                „,/ 

not   in 

TA 

// 

/ 

.  .*/ 

/ 

? 

C 

& 

T 

s* 

.0.20 

123456789         10 
Thickness  of  sheets  to  weld  in  millimeters 

Fig.  4 


11 


ing  purposes  contains  many  impurities,  very  variable  in  nature 
in  consequence  of  the  combustibles  used  in  its  manufacture. 
These  impurities  have  a  great  influence  on  the  quality  of  the 
work,  and  are  such  as  to  preclude  the  certainty  that  the  welds 
made  by  this  process  will  withstand  any  pressure,  even  if  the 
greatest  caution  is  observed. 

(c}      Conclusions. 

On  the  whole,  and  if  the  above  curves  of  cost  prices  are 
taken  in  consideration,  the  oxyacetylene  process  is  more  ad- 
vantageous than  the  oxygas,  except,  however,  as  regards  the 
cost  of  installation.  Hence  the  oxygas  process  should  only 
be  preferred  to  oxyacetylene  in  cases  where  the  cost  of  in- 
stallation has  to  be  taken  into  account,  where  the  plates  to  be 
united  are  not  thicker  than  1/6  to  1/5  inch,  and  where  the 
quality  of  the  weld  obtained  is  of  secondary  importance  only. 

CONCLUSIONS. 

The  above  has  shown  the  advantages,  in  portable  appa- 
ratus, of  dissolved  acetylene  over  hydrogen,  and  in  stationary 
apparatus,  of  generator  acetylene  over  coal  gas. 

When  should  "pressure"  acetylene  or  "generator"  acetylene 
be  used? 

It  is  evident  that  liquid  acetylene  imposes  itself  in  all  cases 
where  the  possession  of  a  portable  apparatus  is  necessary  for 
work  outside  of  the  shop,  or  in  the  shop  on  pieces  difficult  to 
handle,  and  also  when  the  work  to  be  done  is  of  short  duration. 

The  smaller  initial  expense  and  the  easy,  perfect  control  of 
the  consumption  are  also  in  favor  of  dissolved  acetylene  for 
experiments,  studies  and  regulation  of  new  manufactures. 

On  the  other  hand,  the  cost  price  of  the  work  will  become 
the  most  important  factor  in  steady  manufactures,  and  prefer- 
ence will  then  be  given  to  generator  acetylene,  if  the  plant  has 
enough  room  for  the  installation  of  the  generator. 

The  generator  will  also  be  available  in  shops  not  provided 
with  a  practical  system  of  lighting,  or  if  acetylene  is  desired  as 
an  emergency  system  of  illumination,  as,  for  instance,  when  the 
motors  are  out  of  commission  in  shops  electrically  lighted. 

12 


CHAPTER  II. 

DESCRIPTION   OF  OXYACETYLENE  WELDING  PLANTS. 

With  reference  to  the  various  parts  of  the  apparatus  the 
welding  installations  may  be  grouped  in  two  classes : 

ist.  The  combustible  gas  and  the  gas  supporting  the  com- 
bustion enter  the  blow-pipe  under  rather  high  pressures  (in 
general  7  to  15  pounds  per  square  inch),  in  order  to  insure  to 
each  sufficient  velocity  at  the  mouth  of  the  pipe.  This  refers 
to  the  following  installations :  Oxyhydric,  dissolved  acetylene 
and  generator  acetylene  under  pressure. 

2d.  One  of  the  gases,  generally  the  combustible,  is  obtained 
from  a  source  where  the  pressure  is  only  a  few  ounces,  and 
the  other  gas  must  flow  under  a  pressure  sufficient  to  draw 
out  the  first  and  insure  a  proper  velocity  to  the  mixture  at  the 
mouth  of  the  blow-pipe.  Such  are  the  installations  of  oxygas 
and  generator  acetylene  without  pressure. 

INSTALLATIONS    USING    BOTH    GASES    UNDER    PRESSURE. 

In  this  class  we  can  make  two  sub-divisions : 

(a)  Both  gases  come  from  tanks  where  their  pressure  is 
higher  than  that  needed  in  the  blow-pipe  (oxyhydric  and  dis- 
solved acetylene  apparatus). 

(&)  One  of  the  gases  is  produced  under  a  pressure  nearly 
equal  to  that  in  the  blow-pipe  (oxyacetylene  under  pressure 
from  generator). 

(a)      Oxyhydric  and  Dissolved  Acetylene  Apparatus. 

The  hydrogen  and  oxygen  used  in  these  processes  come 
from  seamless  steel  tanks,  in  which  they  are  under  a  pressure 
of  150  pounds  per  square  inch.  The  acetylene  is  contained 

13        . 


in  steel  tanks,  completely  filled  with  a  porous  matter  soaked 
in  acetone,  in  which  the  gas  is  dissolved  under  a  convenient 
saturation  pressure  of  about  150  pounds  per  square  inch. 


These  gases,  to  be  used  in  the  blow-pipe,  must  therefore  be 
brought  to  a  lower  pressure ;  this  result  is  attained  by  the  use 
of  regulating  valves  mounted  on  the  tanks.  In  the  actual 
work  these  regulating  valves  are  used  in  conjunction  with 

14 


gages,  constantly  indicating  the  pressure  of  the  gas  in  the 
tank,  and  consequently  how  much  gas  is  left  in  it. 

The  various  valves  and  gages  used  for  oxygen,  hydrogen 
and  dissolved  acetylene  are  almost  similar,  and  differ  only  in 
the  metal  of  which  they  are  made,  but  their,  principle  is  the 
same. 

The  instrument,  Fig.  5,  described  below  is  composed  of  a  cyl- 
indrical box  divided  in  two  parts.  In  one  of  them  A  is'  the 
gage,  in  the  other  B  the  regulating  valve.  The  gas  coming  by 
a  tube  C  passes  through  a  chamber  D  lined  with  a  filtering 
matter,  stopping  the  dust  that  might  be  driven  in  by  the  gas ; 
this  chamber  has  two  orifices ;  one  in  connection  with  the  gage 
tube,  the  other,  incompletely  closed  by  a  needle  point  E,  and 
through  which  passes  the  gas  going  into  the  expansion  cham- 
ber. On  this  needle  point  E  rests  a  lever  F  connected  with 
the  center  of  an  elastic  diaphragm  G. 

Under  this  diaphragm  is  a  spring  which  constantly  main- 
tains the  needle  point  in  close  contact  with  its  seat  when  the 
pressure  on  top  of  the  diaphragm  is  equal  to  the  atmospherical 
pressure  without  regard  to  the  pressure  of  the  gas  in  the  tank. 
On  top  of  the  diaphragm  is  a  second  spring  /,  the  tension  of 
which  is  regulated  at  will  by  means  of  a  screw  K.  Under 
normal  working  conditions  the  pressure  of  the  gas  on  the 
diaphragm  and  the  pressure  of  the  spring  counterbalance  each 
other.  It  follows  that  the  pressure .  of  the  expanded  gas 
depends  only  on  the  tension  of  the  spring,  and  is  independent 
— or  nearly  so — of  the  variation  of  pressure  in  the  flask. 

A  safety  valve  L  placed  on  the  expansion  chamber  limits 
the  pressure  in  that  chamber  to  a  maximum,  which  a  defective 
working  of  the  needle  point  E  might  tend  to  exceed.  A  needle 
point  cock  M,  placed  at  the  end  of  this  chamber,  connects  the 
regulating  valve  and  the  blow-pipe,  and  is  used  to  stop  the 
flow  of  gas  at  any  time  without  being  compelled  to  close  the 
cock  of  the  tank  itself. 

Emanating  from  the  regulating  valves,  the  gases  are  brought 
through  rubber  tubes  of  convenient  diameter  to  the  blow-pipe, 
where  the  mixture  takes  place,  to  be  ignited  at  the  mouth. 

15 


In  the  type  of  installations  now  discussed  both  the  com- 
bustible gas  and  the  supporter  of  combustion  arrive  in  the 
blow-pipe  under  very  nearly  equal  pressures  sufficient  to  insure 
a  speed  of  the  mixture  at  the  mouth  of  the  blow-pipe  slightly 
greater  than  that  of  the  spreading  of  the  flame  through  this 
mixture.  Under  these  conditions,  if  the  working  of  the  appa- 
ratus was  .regular  and  perfect,  there  would  be  no  fear  of  a 
back  draft  inside  of  the  blow-pipe.  Relying  on  this  theo- 
retical impossibility  of  a  back  draft,  under  normal  working 
conditions,  a  number  of  manufacturers  offered,  until  very  re- 
cently, oxyhydric  blow-pipes  having  no  safety  appliances  to 


FIG.    6. 


avoid  a  return  of  the  flame  inside  of  the  apparatus.  But  if 
for  any  reason  (defective  working  of  a  regulating  valve, 
insufficient  pressure  in  a  tank,  smashing  or  folding  of  a 
rubber  hose,  contact  of  the  end  of  the  blow-pipe  with  the  pipe 
to  be  welded,  etc.)  the  speed  at  the  mouth  became  for  an 
instant  inferior  to  that  practically  necessary,  the  blow-pipe 
became  red  hot,  burning  the  workman's  hand,  and  the  flame 
ran  back  as  far  as  the  rubber  tubes,  which  were  burned;  the 
valves  had  to  be  instantly  closed  and  everything  put  in  shape 
again. 

In  the  oxacetylene  blow-pipe  of  the  Dissolved  Acetylene 
Company  the  safety  appliance  is  located  inside  of  the  appa- 
ratus ;  the  back  draft  is  avoided  by  a  particular  construction, 
by  which  the  mixture  of  acetylene  and  oxygen  convenient  for 
the  welding  flame  takes  place  in  a  very  small  space  near  the 
mouth  of  the  blow-pipe.  From  this  mouth  to  the  source  of  the 
gases  the  quantity  of  acetylene  in  the  mixture  decreases.  The 
explosive  wave,  coming  in  contact  with  parts  of  gas  of  de- 

16 


creasing  explosive  power,  slackens  rapidly.  The  result  is  a 
very  reduced  localization  of  back  drafts.  This  appliance  is 
also  completed  by  the  interposition,  in  the  supply  pipe  of 
acetylene,  of  a  porous  screen,  which  effectively  stops  the  flame, 
a  result  that  could  not  be  obtained  by  a  cushion  of  wire  gauze, 
contrary  to  general  belief. 

(&)  Oxacetylene  Installations  with  Generator  Producing 
Acetylene  Under  a  Pressure  of  About  7^2  Pounds. 

The  blow-pipes  employed  in  this  case  may  be  simply  mixers 
of  gas,  as  above,  with  the  condition,  however,  that  the  pres- 
sure of  the  acetylene  supplied  by  the  generator  be  sufficient  to 
insure  to  the  mixture  a  speed  at  the  mouth  superior  to  that 
of  the  spreading  of  the  flame  (a  condition  which  is  generally 
realized  in  these  instruments).  But  the  installation  is,  how- 
ever, different  from  the  others.  If  we  suppose  that  for  some 
reason  one  of  the  gases,  through  an  excess  of  pressure,  has  a 
tendency  to  enter  the  flask  containing  t*he  other  gas,  it  is 
easy  to  understand,  by  referring  to  the  description  of  the  above 
regulating  valves  and  manometers,  that  the  construction  of  this 
apparatus  renders  impossible  the  connection  of  one  of  the 
tanks  with  the  other. 

In  the  case  of  installations  with  generator  producing  acety- 
lene under  a  pressure  of  7^  pounds  the  acetylene  regulating 
valve  and  manometer  do  not  exist,  and  nothing  would  stop 
the  oxygen  coming  out  of  its  tanks  to  get  into  the  acetylene 
generator.  In  order  to  avoid  this  possibility  of  accident  it  is 
necessary  to  interpose  in  the  acetylene  pipe,  between  the  blow- 
pipe and  the  generator,  a  safety  hydraulic  interrupter.  (See 
Technologic  Bulletin,  December,  1903,  page  1,348.) 

INSTALLATIONS     USING    ONE    OF    THE    GASES    TO    DRAW     OUT    THE 
OTHER. 

The  acetylene  produced  by  ordinary  generators  for  lighting 
purposes  and  the  coal  gas  distributed  in  the  cities  are  under 
a  pressure  of  only  a  few  ounces  of  water. 

The  oxygen  always  comes  from  tanks  where  its  pressure  is 
150  pounds  per  cubic  foot. 

17 


A  regulating  valve  and  manometer,  placed  on  the  oxygen 
tank,  reduce  the  pressure  of  this  gas  to  15  -.pounds,  under 
which  it  is  fed  to  the  blow-pipe.  The  latter  is  provided  with 
an  injector,  the  diameter  of  which  changes  according  to  the 
quantities  of  oxygen  required.  The  oxygen,  acting  as  motor, 
brings  the  combustible  gas  in,  and  in  this  way  it  is  possible  to 


regulate  the  speed  of  the  flame.  This  is  the  principle  of  all  the 
blow-pipes  of  this  class,  the  difference  consisting  of  more  or 
less  perfect  details  of  manufacture. 

The  first  blow-pipe  using  acetylene  without  pressure  has 
been  invented  by  Mr.  Ed.  Fouche  (August,  1877). 

On  account  of  the  considerable  difference  between  the  pres- 
sures of  the  oxygen  and  the  combustible  gas,  and  in  order  to 

18 


avoid  a  flowing  back  of  the  oxygen  in  the  pipes  of  the  com- 
bustible through  any  accident,  it  is  necessary  to  interpose  on 
these  pipes,  and  as  near  the  welding  point  as  possible,  an 


FIG.    8. 

hydraulic  safety  valve.  This  appliance,  Fig.  8,  is  composed  of 
a  central  tube  A  for  the  combustible  gas,  terminated  at  its 
lower  extremity  by  a  bell-shaped  casting,  on  the  circumference 

19 


of  which  are  numerous  holes  through  which  the  gas  escapes, 
reaching  the  blow-pipe  through  the  tube  S\  The  valve  chamber 
is  filled  with  water  to  the  level  of  a  gage  cock  R,  and  is  also 
provided  with  a  safety  tube  B,  the  lower  end  of  which  is 
slightly  below  the  normal  water  level.  The  top  is  connected 
with  a  basin  communicating  with  the  air  outside  by  holes  in 
the  cover. 

In  case  of  an  accidental  flowing  back  of  the  oxygen  in  the 
apparatus,  the  water  rises  in  the  tubes  A  and  B,  and  the  section 
CD  of  the  safety  tube  B  is  uncovered ;  the  gas  escaping  outside 
and  no  flowing  back  can  occur  in  the  central  tube,  which  re- 
mains immersed  in  water. 

The  water  carried  away  is  collected  in  the  upper  basin,  and 
falls  back  to  the  bottom. 

BLOW-PIPES. 

As  previously  said,  all  the  blow-pipes  used  in  these  kinds 
of  installations  are  identical  as  to  principle,  the  only  difference 
between  them  being  the  details  of  manufacture,  rendering  their 
working  more  or  less  perfect  and  their  manipulation  more  or 
less  safe. 

The  safety  appliance  placed  on  the  acetylene  pipe,  avoiding 
all  back  drafts  of  the  flame,  is  one  of  the  most  important  parts 
of  the  welding  tools. 

The  French  company  for  the  dissolved  acetylene  process 
uses  a  porous  material.  In  the  Fouche  system  the  acetylene 
goes  through  a  series  of  very  long  and  very  thin  tubes.  In 
other  cases  an  accumulation  of  metallic  gauzes  is  resorted  to, 
which  is  more  dangerous  than  efficacious,  and  others  solve  the 
problem  by  the  complete  absence  of  the  safety  appliance. 

Although  it  is  not  our  intention  to  describe  the  various 
systems  of  blow-pipes,  we  shall  draw  attention  to  two  systems, 
still  unknown  because  they  are  very  new. 

ist.  Warming  up  of  the  gaseous  mixture  before  its  inflamma- 
tion. 

The  insufficient  temperature  of  combustion  of  coal  gas  led 
to  appliances  for  heating  it.  The  company  using  the  com- 

20 


pressed  gases,  to  attain  this  end,  warms  up  the  oxygas  mix- 
ture by  means  of  a  flame,  bringing  to  red  heat  a  coil  through 
which  the  mixture  passes.  It  is  evident  that  this  disposi- 
tion insures  a  higher  temperature  of  combustion,  but  its 
slow  action  speaks  against  it.  At  the  moment  of  lighting,  the 
coil  is  cold,  and  the  heater  has  no  action  on  the  mixture ;  its 
action  is  only  progressive,  following  the  warming  up  of  the 
coil,  so  that  this  disposition  is  only  interesting  in  cases  where 
the  blow-pipe  must  work  without  stopping  for  a  long  time. 
This  disposition  is  of  no  value  in  the  works  necessitating  the 
lighting  of  the  blow-pipe  for  only  short  periods. 

2d.  Blow-pipes  with  interchangeable  heads  for  various  sizes 
of  flame.    To  facilitate  the  work,  and  to  reduce  the  consump- 


FIG.    9. 

tion  of  gas  to  a  minimum,  it  is  necessary  to  use  blow-pipes 
giving  a  flow  of  gas  in  proportion  to  the  work  to  be  done. 
In  the  case  of  a  blow-pipe  where  one  gas  brings  in  the  other, 
the  sections  of  the  injector  and  of  the  pipes  for  the  gas  carried 
in,  the  shape,  the  sections,  and  the  length  of  the  mixing  and 
egress  chambers  must  be  well  determined  for  a  given  flow.  The 
result  is  the  necessity  of  making  a  blow-pipe  for  each  of 
the  necessary  flows.  Undoubtedly,  certain  manufacturers  have 
pretended  that  they  obtained  flames  of  different  volumes,  in 
which  the  mixture  of  the  gases  was  perfect,  with  the  samfc 
blow-pipe,  the  same  injector,  the  same  mixing  parts,  by  simply 
changing  the  mouth  of  the  blow-pipe.  This  assertion  has  no 

21 


foundation,  and  experience  has  shown  the  imperfect  working 
of  these  blow-pipes. 

By  a  special  adjustment  of  its  blow-pipes  the  B.  R.  C.  Com- 
pany has  realized  the  grouping  in  a  head  easily  removable  of 
all  the  parts,  the  form  and  section  of  which  is  variable  with 
the  required  flow.  The  result  is  that  with  only  one  body  of 
blow-pipe  and  a  series  of  these  removable  heads,  it  is  possible 
to  obtain  a  great  variety  of  flows,  rendering  possible  the  ex- 
ecution of  very  different  classes  of  work. 

This  disposition  is  of  value  for  the  shops  where  oxyacety- 
lene  welding  is  seldom  made,  and  on  pieces  of  very  different 
thicknesses. 

3d.  General  comparison  between  the  blow-pipes  of  the  first 
class  (ga>s  under  pressure}  and  those  of  the  second  class  (one 
gas  driving  in  the  other.} 

Certain  shops,  noticing  marked  differences  between  the  work 
obtained  with  the  same  gases  (acetylene  and  oxygen),  but  in 
one  case  with  blow-pipes  of  the  first  class  (gas  under  pres- 
sure), and  in  the  other  with  blow-pipes  in  which  one  gas 
forces  in  the  other,  came  to  the  conclusion  that  the  former 
were  superior  to  the  latter. 

This  superiority,  although  real,  is  not,  however,  as  great  as 
one  might  be  tempted  to  believe,  because  if  certain  blow-pipes 
where  one  gas  brings  the  other  in  are  not  carefully  watched, 
the  few  types  generally  used  in  the  shops  admit  of  a  complete 
mixture  of  the  gases  and  of  a  perfect  mixture,  the  flame  of 
which  is  in  all  respects  similar  to  that  of  the  other  blow-pipes. 

The  inferiority,  if  it  may  be  so  called,  of  the  blow-pipes  of 
the  second  class,  arises  from  the  following  fact: 

When  the  workman  starts  to  work  and  regulates  the  flame 
of  his  blow-pipe,  its  mouth  is  at  the  same  temperature  as  the 
surrounding  air.  In  the  course  of  the  work  the  diameter  of 
this  mouth  increases  in  a  certain  proportion  on  account  of  the 
heat;  on  the  other  hand,  particles  of  melted  metal  or  oxide 
are  always  projected  and  may  obstruct  this  mouth  more  or 
less.  The  result  is  that  the  volume  of  the  issuing  mixture 
is  variable  during  the  work. 


In  the  blow-pipes  where  the  gases  come  in  under  the  same 
pressure  this  modification  of  the  diameter  of  the  mouth  has 
no  other  consequence  than  a  variation  of  the  flow;  the  pro- 
portion of  the  gases  in  the  mixture  does  not  change,  and  it 
follows  that  the  nature  of  the  flame  is  not  modified. 

On  the  contrary,  in  the  blow-pipes  where  one  gas  carries  in 
the  other,  the  quantity  of  oxygen  passing  under  high  pressure 
through  the  injector  remains  nearly  constant,  notwithstanding 
the  variation  of  the  orifice  area,  whereas  the  quantity  of  acety- 
lene carried  is  subject  to  fluctuations.  The  consequence  is  a 
certain  irregularity  of  the  flame,  generally  hardly  noticeable, 
requiring  only  a  closer  watch  on  the  part  of  the  workman. 


CHAPTER  III. 

APPLICATIONS    OF    THE    HIGH    TEMPERATURES    FURNISHED    BY    THE 
BLOW-PIPES. 

The  high  temperatures  that  are  so  easily  obtained  by  the  use . 
of  blow-pipes  have  admitted  of  the  execution  of  certain  in- 
dustrial works  which  were  before  impossible.  We  shall  not 
speak  here  of  the  cutting  up  of  metals,  which  will  be  the 
subject  of  a  future  article,  but  shall  only  indicate  a  few  of 
the  applications  of  oxyacetylene  welding,  limiting  of  necessity 
our  description  to  the  most  typical  current  work.  In  fact,  to 
enumerate  all  the  cases  where  oxyacetylene  welding  has  been 
the  cause  of  any  saving  it  would  be  necessary  to  review  all  the 
branches  of  metallurgic  activity. 

BLOW-PIPE    WELDING    OF     STEEL    PLATE. 

One  of  the  most  important  applications  of  oxyacetylene 
welding  is  its  substitution  for  riveting  and  bolting  in  steel- 
plate  work. 

To  assemble  steel  plates,  and  in  general  in  all  cases  of  as- 
semblage by  oxacetylene  welding,  "marking"  is  the  first  opera- 
tion; it  consists  in  making  in  various  places  along  the  pieces 
to  be  assembled  several  "drops"  of  welding,  in  order  to  main- 
tain the  two  parts  to  be  united  in  their  respective  positions. 
Then  welding  is  done  in  the  following  way: 

AB,  AB'  are  the  edges  of  the  two  plates  to  be  united,  pre- 
viously marked  (Fig.  10). 

We  suppose  that  we  start  welding  at  a,  moving  forward 
toward  BB'.  The  flame  of  the  blow-pipe  is  .allowed  to  act  at 
the  point  a  until  it  causes  a  fusion  of  the  metal  throughout  the 

24 


plate  at  a;  the  metal  in  fusion  affects  the  shape  of  a  drop.  The 
flame  is  then  brought  forward  from  a  to  b;  at  b  the  same 
operation  is  repeated,  and  so  forth. 

In  fact,  the  successive  fusion  drops  a,  b,  c,  etc.,  partially  cover 
each  other,  and  after  cooling  form  an  homogeneous  mass. 

The  exterior  face  of  the  welding  alone  shows  the  way  in 
which  the  work  was  done  by  a  series  of  ridges  outlining  the 


B  B 


1 

c 

X 

) 

€ 

X 

I 

} 

* 

/ 

V. 

J: 

/ 

A 

FIG.   10. 

successive  fusion  drops.  These  ridges  are  more  or  less 
apparent,  according  to  the  ability  of  the  workman  and  to  the 
volume  of  the  fusing  drops,  the  latter  being  in  proportion 
to  the  thickness  of  the  plate. 

In  the  assembling  of  two  plates  by  oxyacetylene  welding  the 
quantity  of  lost  metal  (by  oxidation,  for  instance,)  being  ex- 
ceedingly small,  the  thickness  along  the  welding  line  is  prac- 


tically  the  same  as  the  adjoining  parts,  if  there  is  no  ma- 
terial space  between  the  two  parts  to  be  welded.  -If,  on 
the  other  hand,  there  is  a  space  between  them,  it  is  neces- 
sary, after  the  edges  of  both  plates  have  been  brought  to 
the  melting  point,  to  melt  a  rod  of  the  metal,  which  the  work- 
man holds  in  his  hand;  this  supplementary  metal  falls  by 
drops  on  the  melted  edges  and  increases  the  melted  mass  in 
the  proportion  desired.  The  nature  of  this  supplementary 
metal  varies  with  the  result  to  be  obtained.  Very  often,  in 
order  to  have  an  invisible  welding  line  and  not  to  modify  the 
qualities  of  the  metal  along  the  latter,  this  line  is  "charged"  by 
means  of  metal  taken  from  the  piece  itself,  such  as  strips  taken 
from  the  plates;  more  frequently,  in  the  case  of  iron  or  soft 
steel,  the  "charge"  is  made  by  means  of  ordinary  soft  steel 
wire,  Y§  to  %  inch  diameter,  according  to  the  thickness  of  the 
piece  to  be  soldered.  The  quantity  of  metal  so  added  varies 
with  the  space  between  both  parts  before  welding,  and  with 
the  excess  of  thickness  to  .be  given  to  the  welded  part  over 
the  adjoining  metal ;  naturally,  this  excess  of  thickness  may 
be  as  great  as  the  particular  conditions  may  require,  but  in 
general  it  is  very  small,  and  a  little  chipping  or  filing  is  enough 
to  take  away  the  unevenness  and  bring  the  welded  part  to  the 
level  of  the  adjoining  surface. 

Thin  plates  (less  than  1/16  inch  thickness)  to  be  welded 
with  the  blow-pipe  require  no  special  preparation  of  the  edges 
before  assembling.  The  above  sketches  show  the  various  cases 
to  be  considered: 

Fig.  ii.  Angle  of  the  plates  less  than  90  degrees  (concave 
bottom  welded  in  a  shell). 

Fig.  12.  Angle  of  the  plates  about  90  degrees.  The  as- 
sembling may  be  made,  as  desired,  according  to  sketch  A 
or  B.  Assembling  A  requiring  no  addition  of  metal  is  more 
rapid. 

Fig.  13.  Angle  of  the  plates  larger  than  90  degrees  (convex 
bottom  welded  in  a  shell). 

Fig.  14.  Angle  of  the  plates  =  180  degrees. 

The  welding  of  plates  of  more  than   ^  mch  thickness  re- 

26 


quires  a  special  chamfering  of  the  edges.  These  sketches 
show  various  examples.  In  general  the  preparation  must  be 
such  as  to  allow  the  flame  of  the  blow-pipe  to  penetrate  to  the 
very  bottom  of  the  part  to  be  welded ;  thus,  there  is  no  doubt 
that  the  entire  thickness  is  affected.  If  in  some  cases  it  is 
impossible  to  make  such  a  preparation  it  is  then  necessary  to 
proceed  slowly,  in  order  to  thoroughly  fuse  the  entire  section 


Pig.  11 


Fig.  12 


s 


1 


_J 


Fig.  13 

of  the  metal.    In  this  case  it  will  be  better  if  the  plates  to  be 
assembled  are  not  in  contact  but  are  1/16  inch  apart. 

Fig.  15.  Angle  of  the  plates  less  than  90  degrees.  Prepara- 
tion A  is  better  than  B. 

Fig.  16.  Angle  of  the  plates  90  degrees.  Preparations  A 
and  C  are  better  than  B. 

Fig.  17.  Angle  of  the  plates  larger  than  90  degrees. 

Fig.  18.  Angle  of  the  plates  =  180  degrees. 

The  most  delicate  welding  is  that  of  pieces  with  re-entering 
angles.  This  is,  however,  seldom  the  case;  but  if  such  is  the 
case  it  is  better,  if  possible,  to  prepare  the  piece  according  to 
sketch  20  or  21,  or,  if  any  advantage  results  from  it,  according 
to  sketch  22  or  23,  a  rigid  rib  being  obtained  which  prevents 
deformations  of  the  piece. 

27 


Before  welding 


Before  welding  After  welding 


_J 


L_ 


Fig.  16 
Before  welding  After  welding 


Fig.  17 


In  general,  in  preparing  plates  to  be  assembled  by  oxacet>- 
lene  welding  care  should  be  taken  not  to  imitate  shapes  pre- 
viously requiring  bolting  or  riveting. 

In  the  majority  of  cases  oxacetylene  welding  does  away  with 
a  lot  of  preparatory  work ;  calking  of  edges,  pulling  apart  of 
rivets  and  other  fastenings,  operations  always  expensive  and 
which  are  always  to  be  avoided  if  possible. 

Let  us  consider,  for  instance,  the  case  of  a  cylindrical  tank 


Fig.  18 


Fig.  23 


with  riveted  bottom  and  head.  If  this  tank  is  not  of  a  suf- 
ficient diameter,  and  is  not  provided  with  a  manhole,  it  will 
be  necessary 'to  make  it  with  at  least  a  convex  bottom  or 
head.  Anyway,  its  making  requires  a  riveted  cylindrical  shell 
with  two  drawn  heads  at  the  ends  to  permit  the  riveting  of 
bottom  and  head  and  riveted  bottom  and  head  with  calked 
edges. 

The  same  tank  can  be  made  by  oxyacetylene  process  with 
solid  welded  heads. 

29 


We  may  remark,  in  passing,  that  oxacetylene  welding  has 
rendered  possible  the  making  (volume  and  resistance  being 
equal)  of  tanks  less  cumbersome  and  lighter  than  those  used 
before  its  advent,  in  that  it  has  made  possible  the  building  of 
tanks  with  two  convex  bottoms  without  regard  to  the  diameter 


---800-- 


a>^ 


—  700  — 


r 


FIG.    24. 

and  absolutely  free  of  the  double  thickness  of  plates  necessi- 
tated by  riveted  coverings. 

Nearly  all  the  tanks  built  to  contain  gases  under  pressure 
or  very  thin  liquids,  such  as  petroleum,  are  now  welded  by 
the  oxyacetylene  process,  because  aside  from  the  advantages 
of  weight,  bulk  and  price  which  they  have  over  the  riveted 
tanks,  they  do  not  leak,  a  quality  which  is  difficult  to  obtain 
by  riveting,  and  even  with  subsequent  tin  soldering,  particu- 
larly when  these  tanks  are  supposed  to  travel  and  are,  con- 
sequently, subject  to  continual  rough  handling. 


Aside  from  the  saving  which  may  be  realized  by  oxyacety- 
lene  welding  over  riveting  by  doing  away,  in  a  large  measure, 
with  preparatory  forge  work,  we  must  also  consider  the 
economy  of  this  process  of  assembling  in  itself. 

Let  us,  for  instance,  consider  the  case  of  the  ordinary  rivet- 
ing together  of  two  plates  of  54  mcn- 

ist.    Riveting  (One  Line  of  Rivets}. 

Diameter  of  rivets,  */2  inch;  number  of  rivets  per  foot  =  8. 

Price  paid  to  the  workman  per  foot  of  joint : 

Laying  out  the  holes $   .006 

Marking 0066 

Drilling 0294 

Chamfering 003 

Riveting 0192 

Calking  plates 0048 

Calking  rivets 012 


Total Jo. 0810 

This  cost  of  workmanship,  obtained  in  a  part  of  the  country 
where  the  salaries  are  not  very  high,  does  not  include  the 
general  expenses  arising  from  the  necessary  power,  keeping, 
etc.,  of  the  machinery  (punching  tool,  etc.)  and  heating  of 
the  rivets. 

It  follows  that  riveting  in  one  line  of  rivets  costs  per  foot: 

Eight  £-inch  rivets,  1.23  X  4  cents $  .04 

Workmanship  (without  general  expenses) o  .08 


Total $0.12 

Oxyacetylcne  Soldering   (Generator  Acetylene}. 

Chamfering  of  edges,  per  foot o  .0108 

C  oacetylene $0.0186^ 

Welding •<  oxygen -0312  >•  o .066 

(^  workmanship .0162  ) 


Total $0.0768 

31 


This  example  shows  conclusively  that  assemblage  by  oxy- 
acetylene  welding  is  more  economical  than  by  riveting.  To 
complete  our  comparison  we  shall  consider  the  cases  of  the 
building  of  a  vertical  tubular  boiler — shown  in  sketch  No.  24 — 
by  oxyacetylene  welding  and  by  riveting.  We  shall  not  men- 
tion the  operations,  which  are  similar  in  both  processes  of 
manufacture:  shearing  and  laying  out  of  the  plates,  boring 
holes,  assembling  and  expanding  of  tubes,  etc. : 

ist.     Oxyacetylene  Welding  (Generator}. 

f  Shell,         8.5      ft.  X    $.0054     $   .046 
Chamfering  of  edges •<   Furnace,    2. 925  ft.  X      .0072          .021 

(Uptake,     5.85    ft.  X      .066  .038 

f  Shell,         4.225^.  X      .066       $  .278 
Welding <   Furnace,    1.462  ft.  X      .21  .307 

(   Uptake,      2.925ft.  X      .12  .351 

Rounding  and  planing  after  welding $   .60 

Forging  of  furnace  (uptake  and  mouth) 2 .40 

Turning  of  circular  plates 40 

Assembling  of  the  boiler  (mounter  and  help) 80 

Welding  32. 5  ft.  @  $0.27 8.78 

Total $14.02 

2d.     Riveting. 

Necessary  plate: 

For  shell 5  . 28  pounds 

For  furnace 4 . 62  pounds 

For  furnaces  flanges 9-9°  pounds 

For  flanges  of  the  outer  circumferential  plates,  5 1 . 48,  total 

71.28  pounds,  @  $0.25 $  1.78 

44  ^-inch  rivets,  5  pounds;  275  f-inch  rivets,  112  pounds,  117 

pounds  @  $.04 4.68 

Marking  rivet  holes i .  40 

Flanging  the  uptake  with  forge  heat i  .00 

Closing  in  on  furnace  boiler  head  flanges .80 

Forging  the  furnace  (uptake  and  mouth) 4 .00 

f  Inf.,  105  pounds  X  $0.01          i.oc 
Closing  in  the  flanges  of  the  plate  {  0 

[  Sup.,  132  pounds  X    0.009      1.19 


Turning  of  circular  plates 
Assembling  the  boiler 


Chipping  and  calking  heads i  .60 


Riveting 


Total . '. 123 . 3 2 

The  above  prices  of  riveting  are  established  on  the  sup- 
position that  the  chamfering  and  calking  are  executed  by 
compressed  air  (except  for  the  heads,  which  require  some 
hand  work).  They  do  not  include  the  general  expenses  (ma- 
terial, coal  and  coke  necessary  for  welding  the  charger  and  for 
the  various  forge  work). 

These  results  show  the  considerable  saving  obtained  by  judi- 
ciously using  oxyacetylene  welding  in  boiler  making,  and  ex- 
plain the  development  cf  this  process  as  soon  as  it  was 
known.* 

The  cost  price  may  also  be  made  much  smaller  by  a  pre- 
liminary warming  up  of  the  parts  to  be  welded  by  means  of 
the  "Hauck"  burner,  using  a  less  expensive  combustible  than 
the  oxyacetylenic  or  oxhydric  mixture.  It  is  evident  that  in 
every  instance  where  the  method  of  manufacture,  the  shape  of 
the  pieces,  the  place  where  the  work  is  to  be  done,  will  admit 
of  such  a  warming  up,  a  great  advantage  will  result  by  such 
bringing  of  the  parts  to  be  welded  to  the  highest  practicable 
degree  of  heat;  the  more  expensive  combustible  from  the 
blow-pipe  is  thus  used  only  to  cause  the  actual  welding,  which 
the  cheaper  modes  of  heating  cannot  effect. 

TENSILE    STRENGTH    AND    ELASTICITY    OF    PIECES    WELDED    BY    THE 
OXYACETYLENE    PROCESS. 

The  experiments  conducted  on  plates  welded  with  oxyacety- 
lene, or  oxyhydric  blow-pipes,  show  that  the  results  are  about 
the  same  if  the  proportions  required  to  obtain  a  neutral  flame 


*  These  prices  being  those  usual  in  French  establishments  must  be  proportion 
ately  increased  for  American  plants. 

33 


have  been  well  kept.  The  unfavorable  results  that  may  have 
been  obtained  with  either  one  of  the  methods  were  due  solely 
to  a  defective  regulating  of  the  flame. 

The  tensile  strength  of  pieces  welded  by  the  oxyacetylene 
process  is  practically  the  same  as  that  of  the  metal  itself,  and 
in  general  is  rather  superior. 

On  the  other  hand,  the  elasticity  is  to  some  extent  reduced, 
which  seems  natural,  the  welded  part  having  been  melted  and 
then  rapidly  cooled,  whereas  the  adjoining  parts  have  been  ob- 
tained by  fusion,  followed  by  slow  cooling  or  by  laminating 
or  hammering,  which  operations  increase  the  malleability. 

If  after  welding  care  is  taken  to  anneal  the  piece,  the  elas- 
ticity is  restored  and  becomes  equal  to  that  of  the  metal  in 
the  primitive  state. 

In  cases  where  the  welded  pieces  have  a  tendency  to  stretch, 
it  will  be  well,  whenever  possible,  to  anneal  them  after  weld- 
'  ing;. 'it  will  be  necessary  to  take  this  precaution  in  such  works 
as  boilers,  superheaters,  etc. 

REPAIRS    TO    STEEL    BOILERS. 

In  repairing  in  general,  and  particularly  in  repairing  plates, 
the  use  of  the  blow-pipe  is  indispensable,  because  it  very  often 
happens  that  by  its  use  pieces  may  be  saved  which  otherwise 
would  have  to  be  replaced ;  this  fact  alone  results  in  con- 
siderable economy. 

One  of  the  interesting  applications  of  the  oxyacetylene 
process  is  the  repairing  of  boilers.  Nearly  all  the  work  of  this 
class  accomplished  up  to  the  present  time  has  been  done  with 
dissolved  acetylene,  because  portable  tools  are  most  con- 
venient for  this-  class  of  work,  as  they  avoid  unnecessary 
handling  of  heavy  parts,  and  on  the  other  hand  the  lower 
temperature  of  the  oxyhydric  mixture  renders  its  application 
impossible  in  repairs  where  plates  are  above  ^2  inch  thick. 

For  an  example  we  will  mention  some  of  the  very  interesting 
work  performed  during  the  year  1906  by  the  use  of  dissolved 
acetylene  by  the  Societe  1' Acetylene  dessous  du  Sud-Est  in 
the  harbor  of  Marseilles. 

34 


1st.  Repairing  Cracks  Steamer  "Eugene  Pereire"  of  the 
French  Line,  March,  1906. 

The  boiler  furnaces  of  the  mail  steamer  Eugene  Pereire  of 
the  French  Line  had  numerous  horizontal  cracks  above  the 
grate  bars.  There  were  about  100  of  these,  and  in  two 
of  the  furnaces  they  extended  from  end  to  end  of  the  corruga- 
tions. 

It  had  been  attempted  to  stop  the  worst  of  these  by  plugging ; 
but  it  would  have  been  necessary  to  renew  several  furnaces, 
which  would  have  detained  the  steamer  for  two  months  and 
caused  great  expense.  All  the  cracks  were  wedged  open  with 
chisels  and  welded;  all  repaired  parts  were  annealed  with 
burners.  In  two  spots  where  there  were  several  adjoining 
cracks,  a  part  of  the  furnace  was  cut  out  and  replaced  by  a 
welded  piece.  No  leak  was  observed  at  any  of  the  100  places 
so  repaired  at  the  hydrostatic  or  steam  tests. 

Only  the  sweating  of  a  few  drops,  caused  by  trifling  lamina- 
tions, were  discovered,  and  a  little  calking  restored  the  water- 
tightness  at  such  spots.  The  work  lasted  three  weeks  and  cost 
$300.  From  the  month  of  March  of  that  year  the  steamer 
has  been  on  the  Algiers  voyage,  which  is  very  trying  for 
boilers  on  account  of  its  shortness,  the  fires  being  banked  and 
boiler  temperatures  changed  so  frequently.  No  trouble  has 
been  experienced  with  any  of  the  welded  parts. 

2d.  Assembling  of  Welded  Pieces;  Work  on  the  "Marsa," 
June,  1906. 

The  unreliability  of  riveted  patches  on  damaged  boilers  is 
well  known,  particularly  where  the  rivets  are  exposed  to  fire. 
The  use  of  oxyacetylene  welding,  by  which  two  pieces  may  be 
united  end  to  end  without  butt  straps,  brings  the  plates  to 
their  original  condition  and  avoids  all  the  inconveniences  of 
rivets.  The  work  performed  on  the  Marsa  offers  a  remarkable 
example  of  the  results  that  may  be  thus  obtained. 

Of  the  four  furnaces  of  this  steamer,  the  steel  plates  A 
and  B  riveted  top  and  bottom  to  the  fire-box,  and  the  plates 
composing  the  back  end  of  the  combustion  chamber,  C  and  D, 

35 


were  completely  worn  out.  Portions  of  these  plates  18  inches 
to  36  inches  long  were  cut  out  and  replaced  by  welded  pieces, 
as  indicated  in  dotted  lines  on  the  sketch  (Fig.  25.)  This  work 
was  very  successful,  except  on  one  of  the  sixteen  pieces,  which 
was  later  replaced  by  a  riveted  patch.  The  welded  part  of  this 


FIG.    25. 

piece  broke  several  times,  but  observations  made  in  the  case 
showed  a  defective  quality  in  the  plate  to  which  the  new  piece 
was  joined.  The  other  fifteen  held  good.  In  the  course  of  the 
work  it  was  noted  that  the  plates  of  the  bottom  of  the  boilers 
were  badly  eaten  away  at  E  on  a  space  of  about  36  inches ; 
oxyacetylene  welding  was  used  to  restore  these  plates  to 

36 


FIG.   26. 

37 


their  original  condition.  In  some  spots  they  had  been  re- 
duced by  corrosion  to  a  thickness  varying  between  %  and  1/16 
inch. 

3d.    Repairing  Corroded  Parts  on  the  "Cholon." 

Oxyacetylene  welding  may  be  used  to  add  metal  directly  to 
the  surfaces  of  plates,  to  repair  corroded  spots,  such  as  are 
frequently  found  in  various  parts  of  boilers.  The  flame  of  the 
blow-pipe  is  directed  upon  the  plate,  and  when  the  latter 
begins  to  melt  the  workman  presents  to  the  flame  a  bar  of  soft 
steel  about  7  by  7,  which  melts  and  fixes  itself  in  drops  on  the 
corroded  surface. 

The  repairs  of  the  Marsa,  already  referred  to,  give  a  sample 
of  the  value  of  the  welding  process,  but  the  work  performed 
on  the  Cholon,  of  the  Compagnie  des  Qiargeurs  Reunis,  from 
Aug.  20  to  Sept.  20,  1906,  presents  a  still  more  striking  case. 

The  eighteen  corrugated  furnaces  of  this  steamer  were 
badly  eaten  away  on  the  surface.  There  was  corrosion  on 
each  side  and  for  some  distance  above  the  grate  bars. 

The  work  was  difficult  to  perform,  as  the  workmen  were 
compelled  to  be  inside  of  the  boilers ;  and  were  inconvenienced 
by  the  heat  of  the  blow-pipe  flame;  and  the  places  to  be 
welded  were  lower  than  the  workmen's  footing;  10,000  cubic 
feet  of  dissolved  acetylene  and  as  much  of  oxygen  were  used; 
about  200  pounds  of  steel  were  used  to  cover  the  corrosions 
and  restore  the  plates  to  their  original  thickness.  This  work, 
at  a  total  cost  of  $2,400,  avoided  the  replacing  of  eighteen  fur- 
naces, as  originally  ordered  by  the  government  inspectors. 

4th.  Repairing  Boiler  Heads  Worn  by  Corrosion  or  by 
Repeated  Calking. 

A  frequent  fault  in  marine  boilers  is  due  to  the  grooving  of 
the  flanged  furnaces  riveted  to  the  combustion  chamber.  These 
heads  are  under  great  stress  on  account  of  the  expansion. 
Leaks,  which  are  in  some  cases  frequent,  require  calking;  but 
each  calking  reduces  the  width  of  the  collar  or  flange,  and 
after  a  series  of  calkings  the  parts  are  practically  worn  out. 

By  the  use  of  oxyacetylene   welding  such  defects   can  be 


very  easily  repaired.  An  addition  of  material  restores  the 
plates  to  their  original  condition.  The  work  is  at  times  a 
lengthy  one,  but  presents  no  special  difficulty.  Advantage  is 
taken  of  a  preliminary  heating  up  to  reshape,  if  necessary,  the 


piece  to  be  repaired,  to  insure  its  close  contact  with  the  plate 
to  which  it  connects. 

By  making  repairs  as  soon  as  a  defect  is  noticed,  boilers 
may  be  kept  in  perfect  condition  and  last  indefinitely;  such 
repairs  delaying  the  running  schedule  to  an  insignificant 
extent. 

Railroad   companies   are  by  this  process   enabled  to   repair 

39 


their  locomotive  boilers  at  trifling  delay,  and  consequently  to 
reduce  considerably  the  capital  otherwise  tied  up  in  repair 
shops. 

MANUFACTURE     OF     THIN     STEEL    TUBES. 

The  methods  employed  up  to  the  present  time  for  the  manu- 
facture of  seamless  drawn  metal  tubes  are  not  economical 
for  very  thin  tubes,  such  as  bicycle  tubes  or  water  or  gas  pipes 
of  large  diameter. 

Oxyacetylene  welding  solves  this  problem.  The  plates  are 
bent  to  form  the  circle,  the  edges  being  forced  into  close 
contact. 

The  edges  are  welded  by  a  blow-pipe,  the  tube  is  then  drawn 
through  a  form  to  rectify  the  thickness  of  the  metal  and  give 


to  the  tube  the  finished  form,  which  cannot  be  exactly  obtained 
by  bending. 

Tube  manufacture  presents  no  peculiarity;  but  the  large 
number  of  similar  pieces  which  are  made  at  the  same  time  has 
brought  about  the  adoption  of  a  special  welding  process. 

The  rapidity  of  welding  depends  upon  the  power  of  the 
blow-pipe  used,  the  thickness  of  the  parts,  the  total  bulk  of  the 
pieces,  and  on  the  nature  of  the  metal.  In  the  manufacture 
in  quantities  the  factors  do  not  vary ;  the  result  being  that 
the  rapidity  of  welding  is  practically  constant.  It  is,  however, 
evident  that  a  workman,  performing  the  work  by  ordinary  pro- 
cess, cannot,  however  great  his  attention,  maintain  an  abso- 
lutely steady  pace;  the  ordinary  welded  metal  along  the  joint 
is  therefore  irregular,  and  this  spoils  the  outward  appearance 
of  the  work. 

40 


It  is  natural  that  in  these  manufactures  in  great  quantities, 
automatic  movement  of  the  blow-pipe  over  the  joint  must  be 
sought.  The  problem  has  been  solved  as  follows : 

The  tube  T,  Fig.  28,  secured  with  its  two  edges  to  be  united 
in  proper  contact,  is  placed  on  a  carrier  A  moving  on  a  bench 
B.  This  carrier  is  automatically  run  at  the  speed  found  neces- 
sary for  the  thickness  of  metal  to  be  welded.  On  an  extension 
C  of  the  bench  B  is  placed  the  blow-pipe. 

The  work  is  generally  performed  by  a  woman  or  a  boy. 
The  blow-pipe  flame  is  regulated  above  the  seam  to  be  welded ; 


FIG.    29. 

the  carrier  A  is  set  in  motion.  The  tube  runs  under  the  flame 
and  is  automatically  welded. 

The  operator  has  only  to  watch  and  adjust  the  flame  of 
the  blow-pipe  so  that  it  strikes  the  seam. 

This  simple  method  does  not  require  skilled  operators  to 
obtain  sound  welding,  and  if  properly  regulated  the  metal  is 
united  at  all  points  along  the  seam. 

Whenever  the  work  so  warrants  this  automatic  running  of 
the  piece  under  the  blow-pipe  should  be  adhered  to. 

MANUFACTURE  OF   TUBING  OF   SPECIAL    SHAPE. 

We  shall  here  mention  several  special  articles  of  manufac- 
ture which  are  rendered  economically  possible  only  by  the 
application  of  the  oxyacetylene  process :  The  manufacture  of 
partitioned  tubes,  the  partial  partitions  of  which  guide  the 
fluids  circulating  inside ;  manufacture  of  handle  bars,  etc.,  for 
bicycles  (Fig.  29)  ;  the  forming  of  elbows  impossible  to 
obtain  by  bending,  whether  on  account  of  the  small  radius  of 
the  bend  or  of  the  thinness  compared  with  the  diameter. 

41 


In  the  case  of  large  diameters,  and  when  the  regularity  of 
the  shape  is  not  absolutely  essential,  the  elbow  may  be  made 
of  cylinders  welded  together  at  the  desired  angle. 

IRON,   STEEL  AND  BRASS    TUBES. 

As  soon  as  blow-pipes  were  found  satisfactory,  pipe-manu- 
facturing shops  were  provided  with  installations  which  ren- 
dered practicable,  at  small  cost  and  with  absolute  guarantee, 
work  that  had  previously  been  impossible  of  performance. 

At  the  present  time  pipe  manufacturers  in  France  possess 
oxyacetylene  welding  apparatus  by  means  of  which  they  are 
able  to  make  in  short  order  changes  or  repairs  to  their  plants 
which  heretofore  caused  long  delays  and  required  taking 
apart  and  reassembling  of  machinery  and  the  attention  of 
special  workmen. 

End   to   End   Welding. 

When  two  tubes  have  to  be  united  end  to  end,  and  they  are 
not  more  than  3/16  inch  thick,  it  is  only  necessary  to  cut  the 
ends  at  right  angles.  If  more  than  3/16  inch  thick  the  ends 
must  be  chamfered,  and  the  welding  is  then  made  as  men- 
tioned in  the  case  of  plates. 

It  is  thus  possible  to  obtain  coils  the  developed  lenghts  of 
which  attain  miles  without  any  flange  or  other  joints,  which 
completely  avoids  the  leaks  and  the  consequent  hard  and 
costly  work  of  examining  and  replacing  the  gaskets. 

Pipe  Branches. 

Oxyacetylene  welding  avoids  the  making  of  collars  in 
branch  work.  It  is  only  necessary  to  give  to  the  end  of  tube 
A  the  curve  of  tube  B,  with -which  it  is  to  be  connected,  and 
to  fit  it  snugly  into  an  aperture  in  the  latter,  and  bring  the 
parts  under  the  flame. 

Welding  on  Flanges. 

Many  accidents  have  occurred  in  consequence  of  the  de- 
struction of  ordinary  brazing,  due  to  the  voltaic  couple  formed 
by  the  contact  of  copper  and  zinc.  It  is  a  well-known  fact  that 

42 


Before  welding  After  welding 

Fig.  30 


Fig.  31 


a  hammer  stroke  on  an  iron  flange  brazed  on  an  iron  pipe 
results,  in  many  cases,  in  a  failure  of  the  brazing.  Oxy- 
acetylene  welding  absolutely  avoids  this  cause  of  possible 
accident,  as  there  is  no  interposition  of  a  chemically  active 
metal. 

The  work  may  be  performed  as  in  Fig.  31,  by  using  the 
ordinary  flanges  and  making  in  A  an  addition  of  a  proper 
amount  of  metal  to  fill  the  joint  up  solidly.  If  the  diameter  of 
the  flange  is  large  in  comparison  with  its  thickness,  and  trouble 
is  feared  through  the  heating  of  its  center  and  buckling,  it  is 
preferable  to  provide  the  flange  with  a  boss  and  to  make  the 
weld  in  B  (Fig.  32). 

Flange  work  costs  somewhat  more  than  brazing,  unless  care 
has  been  taken  to  bring  the  parts  to  red  heat  by  some  inex- 
pensive fuel  before  the  welding  flame  of  hydrogen  and  acety- 
lene is  turned  on. 

But  the  safety  is  much  greater  if  the  pipes  are  to  be  kept 
at  high  temperature  and  pressure,  such  as  with  superheaters, 
digesters,  etc. 

REPAIRING  OF  CRACKS,   FITTINGS,   ETC.,   IN    IRON    AND  FORGED   STEEL 
PIECES   AND  IN    CAST-STEEL   PIECES. 

By  application  of  the  oxyacetylene  flame,  cracks  and  pittings 
in  any  iron  or  steel  pieces  may  be  repaired  rapidly  and 
economically. 

In  the  case  of  cracks  and  blisters  a  groove  must  first  be 
made  to  enable  the  flame  of  the  blow-pipe  to  reach  the  bottom 
of  the  defect.  The  flame  of  the  blow-pipe  is  then  turned  on 
until  the  metal  reaches  a  white  welding  heat.  A  piece  of 
(preferably  the  same)  metal  is  then  presented  to  the  blast 
until  its  melted  drops  solidly  fill  the  crack. 

Numerous  steel  manufacturing  plants  in  France  now  use 
the  blow-pipe  to  repair  blisters  in  castings,  and  manufacturers 
in  general  find  in  it  a  most  valuable  instrument,  which  prevents 
the  necessity  of  discarding  pieces  in  which  defects  may  be 
discovered,  very  often  after  large  sums  have  been  expended 
for  workmanship.  Portable  apparatus  is  in  this  case  particu- 

44 


larly  handy,  as  the  piece  may  be  repaired  without  taking  it 
from  the  machine-tool  (lathe,  planer,  etc.,)  on  which  it  may 
be  adjusted. 

The  steamer  Le  Gaulois  broke  her  stern  post,  the  section 
of  the  broken  part  being  4  inches  by  9  inches.  The  edges  of 
the  break  were  first  chamfered  with  a  special  acetylene  burner 
in  fifteen  minutes,  and  the  welding  proper  was  then  performed 
in  eight  hours  by  the  use  of  dissolved  acetylene;  1,225  cubic 
feet  of  this  gas  were  consumed.  To  replace  this  stern  post 
would  have  cost  from  $3,000  to  $4,000,  and  detained  the 
steamer  a  considerable  time. 


45 


OVERDUE. 

A?8  27 


1 79283 


